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Alpha Images

Alpha Images.jpg

Alpha Images' is a tool in RpToolsto create or manipulate alpha channel images.

Alpha channel images contain a channel, in addition to red, green and blue for color, which defines places where the image is transparent.

This is used to create transparent, 2D components in SketchUp, or to paste renderings or other images on top of a background.

  • Select the Alpha Image icon: ( Bt trans24.PNG ) to load Alpha Images


Add an alpha channel to an image

Add Alpha channel to image.jpg

Select an image in the disk which will be used to make a new image with an alpha channel. (The new image will have _alpha.png appended to the name.

Alpha Color and Tolerance

  • Click anywhere on the image to determine which color will be used to define the alpha channel.
  • Set the tolerance to broaden the range of the color to make the alpha channel.
As you increase or decrease the tolerance, the alpha channel in the image will be redisplayed to show what part of the image will be made transparent.

Display alpha channel as

Select a color to be used to show where the alpha channel will be placed.

Geometry Settings

This determines the size of the component or image if you want to place the new transparent image into your SketchUp model.

The Offset will be used to move the image out from the origin of the component. This assures that the alpha image is displayed in front of a wall, or other object on which it is placed.

Load new image into SketchUp as

  • Component - creates a component for the transparent image.
  • Material - creates a material using the transparent image as a texture.
  • Image - places the transparent image into SketchUp as an image.
  • Save Only - the new image is saved on the disk, but not placed into SketchUp.


Save current model as an Alpha Image

Saves the current SketchUp model as a raster image with an alpha channel wherever the background appears.

Display Alpha Chanel in an image

Show Alpha Channel.jpg

This can be used to verify that an image has a valid alpha color.

Select a .PNG file with an alpha channel from the disk.

The Alpha Channel in the image will be displayed as a solid color.

Use Display alpha channel as to set the color for the Alpha Channel.


See also